南昌市第二學(xué)期初二數(shù)學(xué)期末測試卷及答案

1解k＜直：如線交，2221解k＜直：如線交，2222014學(xué)年度第二學(xué)期末測試卷八級(初二數(shù)學(xué)參考答案及評分意見說明：果學(xué)生考卷出現(xiàn)不同答案，請根據(jù)學(xué)生表現(xiàn)出數(shù)學(xué)發(fā)展水平參照評分意見的給分標(biāo)給出相應(yīng)分?jǐn)?shù)。一選擇（本題共8小題每小題分，共24）．D2．．4．．A．．8．A、空(本大題共8，小2分共16分．

．11．．，≥．，∶00/200014．乙三解答題本大共3小題每題6分共18分.解：）（0）（40）代入=kx+b

;4k

············································2分2;：·································3分.21一次數(shù)解式：x.···························4分21（2）意：x(x)2

，················分1化簡：.··································分2416∵過點（，7）條線與直線x行，設(shè)線為x；·························分344把（﹣1）入x；得7，3317解：，34∴直線的解式為x，······················分33（2）令=0，得：0x317解得：，4

，∴

的數(shù)為：1、、4；·························分4把于1、3、分別代入yx3

得：y=

3

5、3、、，3∴在線上橫、縱坐標(biāo)都是整數(shù)的點的坐標(biāo)是（，．········分．，，，=+與，直線kx+b與軸于C點則=﹣，分1：1k＜，1211：1k＜，1211∴OC，21∴b2

，解得=．當(dāng)時=-4．

···············4分··············6分四應(yīng)題本大共3小，小8分共24分．解）240，·························································································分348；·························································································分（2）根意得，當(dāng)種子的為元，∴y，································3分當(dāng)＞5時有千的種子按60元計價超分按48元計價，∴y=60×5+48（﹣5）=48x，······················································5分xy關(guān)于數(shù)式為48x(x

·······························分（3）∵540＞300，∴次購子過5kg，∴．解得，答他購買種子的數(shù)量是．····················································8分19解）這些車平均速度是2+50×3+60×4+70×5+80×）15=60km/h3分（2）出現(xiàn)的次最多，則這些車的車速的眾數(shù)70km/h；···················5分（3）有個最中的是第個數(shù)，則中位數(shù)是60km/h．··················8分．解）A同成：50×（-2（分）同學(xué)成績：175+×（-2=（）同學(xué)成績：165+×-）（分）同學(xué)成績：1751×-）（分）9578ABCD四位學(xué)的均是：x4分（2設(shè)同對x題答題由得yy20

（分；解得：同學(xué)答題答題．························································分②同學(xué)，他實答14，答錯3題未答題，得分．··················分五、探題本題共2小，每小題分，共18）．解）箱98﹣49顆)，∵乙箱位數(shù)40，∴小于大于40各(49﹣＝24顆，∴甲箱小于40的有＝＝15顆)，大于40有＝﹣＝(顆)，）112設(shè)直線BC為將B）112設(shè)直線BC為將B（）11設(shè)直線CD為將D（）21甲箱內(nèi)的號碼的中位不能為，∵ab40號在箱，箱內(nèi)有顆球，能有號球）∴甲箱內(nèi)球的號的中位數(shù)不能為40．······································（2）（）可：當(dāng)、箱內(nèi)球的號的中數(shù)同時，甲、箱內(nèi)的量應(yīng)該都是偶數(shù)設(shè)箱的碼于x的量是c顆則大于x的數(shù)也是c顆；乙內(nèi)的碼小于x數(shù)是d顆則于數(shù)量是d顆于是在部98球，于數(shù)（c）大x數(shù)是+d）顆，即～98中數(shù)x．∴

(49

．······················································分．解（，k?k=﹣，1∴3=﹣1，=；························································23交點坐為（，）·······················································（2∵過點線=

x+3垂直，∴設(shè)點A直直線解析為，把A（，）入得，b=1，∴解式為．··························分（3）接其任兩能到6條線，···········································分這些直線中共有相垂直關(guān)系它們分別是：⊥，⊥，CD⊥，DA⊥和⊥BD········································